Technology – Hybrid powertrains options

Permanent Magnet motors like those found in the Prius, degrade in performance at higher temperatures and require a cooling system in the design.They allow for regenerative braking, and this comes with a safety trade off asany time there is motion by the magnets, they produce voltage. Permanent magnets also require rare earth which are expensive and difficult to source.

This type of motor is more pron to wear and tear due to some parts having contact with the spinning shaft. The brushes need to have continuas contact. Hence slowly wearing down.

Materials

There is an impending shortage of many rare raw materials used in the manufacture of hybrid and electric cars. For example, the rare earth elementdysprosium is required to fabricate many of the advanced electric motors used in hybrid cars. However, over 95% of the world’s rare earth elements are mined in China and domestic Chinese consumption is expected to consume China’s entire supply by 2012

While permanent magnet motors, favored in hybrids such as those made by Toyota, often use rare earth materials in their magnets, AC traction motors used in production electric vehicles such as the GM EV1, Toyota RAV4 EV and Tesla Roadster do not use permanent magnets or the associated rare earth materials. AC motors typically use conventional copper wire for their stator coils and copper or aluminum rods or bars for their rotor. AC motors do not significantly use rare earthmaterials. (Shown in the below AC Inductor motors).

3-Phase AC Induction

In contrast, 3-Phase AC Induction motors can be air cooled and therefore have better stamina, but have less power density which means that the weight saved from removing the cooling system is replaced with heavier and more complex gearing for the drivetrain. This more complex transmission gearing is also needed to compensate for the fact that a standard 3-Phase AC Induction motor can be either low-speed high-torque (like a standard vehicles starter) or a high-speed low-torque (like a standard vehicles alternator) but not both. This is the most widly used motor so far. Its characteristics feature a: Simple construction, Low cost and minimum maintenance, High reliablity and high efficiency, needs no extra started motor. There are less parts that can wear out as apposed to a Perminant magnet motor. I.e. there are no brushes or touching parts with the shaft besides the bearings to wear.

An AC motor is an electric motor that is driven by an alternating current. It consists of two basic parts, an outside stationary stator having coils supplied with alternating current to produce a rotating magnetic field, and an inside rotor attached to the output shaft that is given a torque by the rotating field. The induction motor, which turns slightly slower than the supply frequency. The magnetic field on the rotor of this motor is created by an induced current.

Multi-Phase AC Induction

A Multi-Phase AC Induction motor (called a ChorusMotor) co-opts the harmonics that limit motor performance, which means thatit can smoothly change from behaving like a high-torque low-speed motor to behaving like a low-torque high-speed motor, without the need for efficiency
robbing physical gearing that would be required to compensate for a 3-Phase ACInduction motors lower power density.

A Multi-Phase AC Induction motor (called a ChorusMotor) co-opts the harmonics that limit motor performance, which means a that it can smoothly change from behaving like a high-torque low-speed motor to behaving like a low-torque high-speed motor, without the need for efficiency
robbing physical gearing that would be required to compensate for a 3-Phase AC Induction motors lower power density.

But wait! Doesn’t this need more batteries to provide the increased current?

Actually no, as a Capacitor (or “UltraCapacitor”) can provide that 10-15 seconds of greatly increased current that is needed for this “Burst” torque.